1. Field of the Invention
This invention is an automatic transmission in which the turbine of a first fluid coupler normally is connected directly to a sun gear of a primary planetary gear set. The output from the transmission is connected to the planet carrier of the primary gear set and means are provided to control the rotation of, and the torque applied to, the ring gear of the primary planetary gear set. In broad terms, if a positive rotation is imparted to the primary sun gear while the output, or the planetary carrier, is stalled, the primary ring gear will tend to rotate negatively unless it is restrained. If the primary ring gear is not restrained at all, it will rotate negatively at the appropriate speed so that it deducts from, or subtracts from, the positive rotation of the sun gear to result in a net output of zero from the planet carrier. In basic principle, this invention applies various means to restrict or restrain the tendency of the primary ring gear to rotate negatively, thus applying a net positive torque and rotation to the output from the planet carrier.
2. Brief Description of the Prior Art
The U.S. Pat. No. 3,455,183 to Orshansky discloses a hydromechanical transmission having some similarities to Applicant's transmission. There is a direct input to the sun of a primary planetary gear set, the output is taken from the primary planet carrier and the primary ring gear is controlled through various means so that the overall transmission ratio may be varied. In other respects, the Orshansky device is not similar to the Applicant's transmission. Orshansky does not contemplate or permit the primary ring gear to rotate negatively to subtract from positive rotation of the primary sun gear, and this is one of the major features of Applicant's invention. Also, the Orshansky transmission does not proceed through each stage of operation automatically, but it requires complex hydraulic and other control means to condition the transmission for each phase of its progression. Finally, the present invention will be seen to produce a "regenerative power feed back" in various modes of operation as the result of restraining forces on the primary ring gear, which assists in the transmission of power to the output. To the contrary in Orshansky, most or all of the reaction forces are dissipated in the hydraulic units.